Folding pole for high floor mast

ABSTRACT

An oil well derrick gin pole has the upper ends of its front legs connected to its rear legs, and sheaves supported by the upper ends of the rear legs to aid in raising a mast hinged to the base supporting the gin pole. The rear legs of the gin pole have upper portions that extend above their connections to the front legs, and these upper portions are hinged to the portions of the rear legs below them, whereby the upper portions of the rear legs can be swung backward and down to shorten the rear legs so that they will not interfere with raising an elevated drawworks support into operative position after the mast is erected.

United States Patent [191' Donnally i 0 ]Apr. 16, 1974 FOLDINGPOLE FOR HIGH FLOOR MAST Inventor: Robert B. Donnnlly, Tulsa, Okla.

Assignee: Lee C. Moore Corporation, Tulsa,

- Okla.

Filed: May 11, 1972 1 Appl. No'.: 252,182 f US. Cl....- 52/116, 52/120, 212/46 A Int. Cl. .L' E2lb 15/00, B66c 23/62 Field of Search 52/111, 116, 117, 120,

References Cited UNITED.STATES PATENTS 3,483,938) 12/1969 Dyereta'lUh; .;52/ll6X Davidson et al. Woolslayer et al. Woolslay'er et al. 52/120 9/1966 Woolslayeretal 52/116 x Primary Examiner-Price C. Faw, Jr.- Attorney, Agent, or Firm-Brown, Murray, Flick &

Peckham [57] ABSTRACT An oil well derrick gin polehas the upper ends of its front legs connected to its rear legs, and sheaves supported by the upper ends of the rear legs to aid in raising a mast hinged to the base supporting the gin pole. The rear legs of the gin pole have upper portions that extend abovestheir connections to the front legs, and

these upper portions are hinged to the portions of the rear legs below them, whereby the upper portions of the rear legs can be swung backward and down to shorten the rear legs sothat they will not interfere with raising an elevated drawworks support into operative position after the mast is erected.

3 Claims, 9 Drawing Figures saw 1 ur 5 a 1 r W L| 1 Ti I 4 v n v PATENIEIJAPR 16 m4 PATENTEDAPR 16 1914 I v sum 2 or 5 PATENTEDAPR-IS m4 l803J8O sum 3 or 5 I PATENTEDAPR 15 1974 SHEET t (1F 5 I ATENTEBAPR 16 I974 SHEET 5 [IF 5 FOLDING POLE FOR HIGH FLOOR MAST It is common practice to raise a reclining oil well mast with the help of a gin pole andthe drawworks of the derrick. Raising or" swinging up the mast is accomplished by first connecting the travelling block to a sling that extends back around sheaves supported by the gin pole and then forward to anchor points on the mast. When the drawworks is operated to reel in the fast line, the travelling block and the sling lift the mast and swing it up to upright'position against the gin pole. As masts become taller and heavier, the strain on the lines becomes greater during raising of the mast, especially during the first part of its upward movement from a substantially horizontal position. One way to reduce the stresses would be to use a taller gin pole, which would elevate the gin pole sheaves around which the sling extends and thereby provide a better angle between the sling and the reclining mast. However, such an upper extension of the gin pole would interfere with the elevated support for the drawworks when a mast is used that has a working floor approximately at the level of the top of an ordinary gin pole.

It is among the objects ofthis invention to provide an oil well derrick substructure in which a hinged mast is provided with a high working floor, in which the drawworks is mounted .on a support at a low level during raising of the mast and then is elevated to a position behind the working floor, in which the gin pole during raising of the mast extends a considerable distance above the level to which the drawworks support will be raised, and in which the upward extension of the gin pole can be moved out of the way after the mast has been raised and before the drawworks support is raised.

The preferred embodiment of the invention is illustrated in'the accompanying drawings, in which FIG. 1 is a side view of a mast base with'the gin pole and drawworks in their lower positions;

FIG. 2 is a side view showing the gin pole erected and a mast attached to the base and partly raised;

FIG. 3 is a side view with the mast erected and the top of the gin pole folded down;

FIG. 4 is a side view showing the drawworks in raised position;

FIG. 5 is an enlarged side view of the fully erected gin pole as seen in FIG. 2;

FIGS. 6, 7 and 8 are views taken on the lines VIVI, VlI--VII and VIII VIII, respectively, of FIG. 5; and

FIG. 9 is an enlarged side view of the drawworks support in its upper position.

Referring to FIG. 2 of the drawings, a relatively low base or substructure l of an oil well derrick is provided toward its front end with shoes 2 in which the foot of a reclining mast 3 is pivoted on a horizontal axis. The mast extends a considerable distance forward from the substructure and may be supported in substantially horizontal position'on trestles as shown in dotted lines. Also mounted in the shoes are the lower ends of the front legs 4 of a ginpole behind the mast. These legs are inclined upwardly and rearwardly and are pivoted at pivot 5 to rear gin pole legs 6, the lower ends of which are pivotally mounted in shoes 7 on the substructure.

Behind the main substructure the drawworks 8 and its engine 9 or engines are located. A fast line 10 from the drawworks extends up and over a roller 11 supported by the gin pole at approximately the level of the connection between the front and rear legs of the gin pole. From this roller the line extends forward to the crown block 12 at the front end or head of the reclining mast and then back in the mast to the travelling block 13. The travelling block is hooked onto the central portion of a sling line 16 that extends rearwardly from both sides of the block around further sheaves l7 and 18 mounted in the mast and then back to the gin pole, where the sling line preferably extends around a pair of sheaves l9supported by the gin pole and then forward again to where the ends of the sling line are anchored to brackets 20 on the back of the mast.

In gin poles known heretofore the sling line sheaves would be mounted in the gin pole at about the same level as the fast line roller. That would mean that the sling line would make quite a flat angle with the reclining mast so that the gin pole and cables would be under great strain in starting to swing the mast upwardly. To avoid this problem the rear legs of the gin pole are extended upwardly several feet and the sling line sheaves are mounted on their upper ends. This provides a much better angle between the sling and the reclining mast. However, this presents another problem because it is intended that the drawworks should be raised to the elevation of the high floor 21 in the mast after the mast has been swung up to upright position. Thus, the drawworks is mounted on a support 22 pivotally connected to the rear ends of a pair of parallel legs 23, the front ends of which are pivotally mounted in the lower part of the rear end of substructure 1. After the mast is raised the sling is disconnected from the back of the mastand is attached to the front of the drawworks support. Further raising of the travelling block in the mast by means of the drawworks will cause the fast line and the sling line to swing the drawworks support upwardly andforward on its pivoted legs. However, with the unusual gin pole described thus far it will be seen that the drawworks support would be prevented by the upper extensions of the rear legs of the gin pole from moving forward against the back of the mast so that it could be attached tothe mast.

Accordingly,-it is a feature of this invention that the upper extensions of the rear gin pole legs can be folded down out of the way of the drawworks support as soon as the erected mast has been attached to the gin pole, as shown in FIGS. 3 and 4, so that the gin pole will not prevent the drawworks support from being fastened to the mast. As shown in FIGS. 5, 6 and 7, each of the two rear legs 6 of the gin pole is therefore formed in part from a front brace 25 that is pivoted to the rear shoes 7 and that extends upwardly and across the upper end of the gin pole leg 4 in front of it. The rear leg is provided with an upwardly extending bracket 26 so that a cooperating bracket 27 (FIGS. 2 and 9) on the heel of the upright mast can be pinned to it. A rear brace 28, also forming part of the rear leg, is pivotally connected at its lower end to brackets 29 projecting from the back of the lower portion of the front brace. The rear brace extends upwardly more nearly vertically than the front brace. This rear brace is held in its operative position shown in FIG. 5 by a removable locking pin 30 extending through brackets 29 and engaged by the lower end of the brace in front of its pivot. When this pin is removed, the rear brace can be swung forward against the front brace, with their ends near each other.

Rigidly connected to the upper end of each front brace 25 is a pair of laterally spaced, upwardly and rearwardly extending brackets 32, in the upper ends of which the lower end of a front link 33 is pivotally connected by a pin 34. The lower ends of these brackets are connected by a plate 35 that rests on and is secured to top plate 36 extending across the upper end of the front leg. The link is inclined upwardly and rearwardly and supports a pair of laterally spaced plates 37 at its upper end. One of the sling line sheaves 19 is rotatably mounted between the upper ends of these plates. The lower portions of the plates project rearwardly and are pivotally connected by a pin 38 to the upper end of a rear link 39 aligned with the rear brace. The lower end of this link is connected by pivot pins 40 to the upper end of the rear brace. Front and rear links 33 and 39 form parts of rear legs 6. The front braces 25 at opposite sides of the gin pole are rigidly connected by a horizontal cross beam 41 secured to them near their upper ends as shown in FIG. 8. It is on the central portion of this beam that the fast line roller 11 is mounted.

After the mast has been raised with the help of the gin pole in its extended operative position shown in FIG. 2, the sling line is disconnected from mast brackets and the gin pole and connected to the front of drawworks support 22. Then the locking pins 30 at the lower ends of the rear braces 28 of the gin pole rear legs are withdrawn to allow the upper ends of those braces to be swung forward against the front braces. This causes the rear links 39 to likewise be swung forward toward the front links, with the result that both links swing backward and fold down over the upper portions of the rear braces as shown in FIG. 3 to reduce the height of the gin pole below mast brackets 27. The drawworks now is operated to cause the fast line and the sling line to lift the drawworks support. Due to this support being mounted on the pivoted parallel legs 23, lifting of the support causes the legs to swing it forward as it rises until the front portion of the support moves across the top of the folded gin pole and engages the back of the mast, as shown in FIGS. 4 and 9, to which it then can be attached. The folded gin pole is out of the path of movement of the drawworks support. In order to lower the mast, the-operations just explained are conducted in reverse order.

Before the gin pole is erected and the mast hinged to the substructure, the folded gin pole is laid in the substructure and its rear legs are connected to the rear shoes as shown in FIG. 1. Then a truck winch line 45 or the like is attached to the front end of the reclining gin pole and pulled to swing the gin pole up until the lower ends of its front legs can be swung forward and attached to the front shoes as shown in dotted lines in FIG. 1. The gin pole is then unfolded to increase its height and the mast is pivotally connected to the front shoes.

According to the provisions of the patent statutes, 1 have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. The combination with an oil well derrick substructure, of a gin pole mounted on the substructure to aid in erecting a drilling mast reclining in front of the gin pole, a drawworks support behind the gin pole; the gin pole having a pair of front legs and a pair of rear legs, means securing the upper ends of the front legs to the rear legs, the upper portions of the rear legs extending above said securing means, means at the upper ends of the rear legs for engagement by a mast-raising sling line, and means hinging said upper portions to the portions of the rear legs below to permit the upper portions of the rear legs to be swung backward and down to reduce the height of the rear legs after a mast has been raised in front of the gin pole; and means for then raising said drawworks support up above the shortened gin pole into the area behind the raised mast occupied by said upper portions of the rear gin pole legs before they were swung down.

2. The combination recited in claim 1, in which each of said rear legs includes a front brace having an upper end terminating adjacent the upper end of the adjoining front leg, a rear brace pivotally connected at its lower end with the lower end portion of said front brace, front and rear links above said braces forming said upper portions of the rear legs, said hinging means connecting the lower ends of said links to said braces, and means pivotally connecting the upper ends of the links together, the front link being inclined backward from the front brace, and the rear link normally being aligned with the rear brace, whereby when the upper end of the rear brace is moved forward the upper ends of the links will be swung back and down and then forward toward the rear brace.

3. The combination recited in claim 1, including parallel front and rear legs pivotally connected to said drawworks support and extending forward therefrom, and means pivotally connecting the front ends of said support legs to the substructure, whereby when said support is raised the support legs will swing it forward over the gin pole. 

1. The combination with an oil well derrick substructure, of a gin pole mounted on the substructure to aid in erecting a drilling mast reclining in front of the gin pole, a drawworks support behind the gin pole; the gin pole having a pair of front legs and a pair of rear legs, means securing the upper ends of the front legs to the rear legs, the upper portions of the rear legs extending above said securing means, means at the upper ends of the rear legs for engagement by a mast-Raising sling line, and means hinging said upper portions to the portions of the rear legs below to permit the upper portions of the rear legs to be swung backward and down to reduce the height of the rear legs after a mast has been raised in front of the gin pole; and means for then raising said drawworks support up above the shortened gin pole into the area behind the raised mast occupied by said upper portions of the rear gin pole legs before they were swung down.
 2. The combination recited in claim 1, in which each of said rear legs includes a front brace having an upper end terminating adjacent the upper end of the adjoining front leg, a rear brace pivotally connected at its lower end with the lower end portion of said front brace, front and rear links above said braces forming said upper portions of the rear legs, said hinging means connecting the lower ends of said links to said braces, and means pivotally connecting the upper ends of the links together, the front link being inclined backward from the front brace, and the rear link normally being aligned with the rear brace, whereby when the upper end of the rear brace is moved forward the upper ends of the links will be swung back and down and then forward toward the rear brace.
 3. The combination recited in claim 1, including parallel front and rear legs pivotally connected to said drawworks support and extending forward therefrom, and means pivotally connecting the front ends of said support legs to the substructure, whereby when said support is raised the support legs will swing it forward over the gin pole. 